Image forming apparatuses are devised to form an image on a printing medium according to received image signals. Examples of image forming apparatuses include printers, copiers, facsimiles and multi-functional devices that combines the functions of several of aforementioned devices.
An image forming apparatus includes, e.g., a body defining the overall outer appearance of the image forming apparatus, a printing medium cassette in which printing media is stored, the printing medium cassette typically being received in the lower region of the body as a slidable drawer, a developing unit that forms a visible image on a printing medium using developer, a pickup unit that picks up and delivers a printing medium from the printing medium cassette to the developing unit, a fusing unit that fixes the developer forming the visible image onto the printing medium and a discharge unit that discharge the printing medium bearing the completed image out of the body.
The printing medium cassette includes a knock-up plate on which the printing media is loaded, an elastic supporting spring that elastically biases the knock-up plate upward and a supporting guide that guides an end of each printing medium loaded on the knock-up plate.
The pickup unit also includes a pickup roller that picks up the printing media loaded on the knock-up plate sheet by sheet, and which, to that end, is arranged to protrude downward so as to come into contact with the upper surface of the uppermost one of the printing media loaded on the knock-up plate.
With such configuration, the downwardly protruding pickup roller may interfere with the movement of the supporting guide when the printing medium cassette is detached and separated from the body of the image forming apparatus. It may thus be necessary to position the upper end of the supporting guide at a height that is lower than the position of the pickup roller so as to prevent the supporting guide from being caught by the pickup roller. Such lowered height of the supporting guide may unfortunately limit the number of printing media that can be loaded in the printing medium cassette.